Water → Hydrochloric Acid

A solution of anhydrous hydrogen chloride in ethanol was prepared by slow addition of acetyl chloride (100 mL) to anhydrous ethanol (500 mL), followed by stirring at room temperature for one hour. 3 (44 g) was added and the solution stirred for one hour. Water (1 L) was added and the solution extracted with methylene chloride (3×). The solvent was removed on a rotovap and the residue dissolved in ethanol. Activated charcoal was added and the mixture stirred for approximately half an hour after which it was filtered through celite. The solvent was then removed on a rotovap. The residue was dissolved in ethanol/water (50:50) (200 mL). Formic acid was added (16 g) followed by 10% palladium/carbon (2.7 g). The solution was warmed to 60° C. and stirred until evolution of gas had ceased. The mixture was filtered through celite. The filtrate was neutralized with aqueous sodium bicarbonate until samples diluted with water were neutral (pH˜7) by analysis with pH paper. The solvent was then removed on a rotovap. Residual water and salt were removed by filtration and azeotropic distillation with ethanol (2×), yielding crude 4 as a yellow oil (33 g).

1. stirringthe solution stirred for one hour
2. extractionthe solution extracted with methylene chloride (3×)
3. customThe solvent was removed on a rotovap
4. dissolutionthe residue dissolved in ethanol
5. additionActivated charcoal was added
6. stirringthe mixture stirred for approximately half an hour after which it
7. filtrationwas filtered through celite
8. customThe solvent was then removed on a rotovap
9. dissolutionThe residue was dissolved in ethanol/water (50:50) (200 mL)
10. additionFormic acid was added (16 g)
11. temperatureThe solution was warmed to 60° C.
12. stirringstirred until evolution of gas
13. filtrationThe mixture was filtered through celite
14. additiondiluted with water
15. customThe solvent was then removed on a rotovap
16. customResidual water and salt were removed by filtration and azeotropic distillation with ethanol (2×)

ORD record

ord-edd3016f0ce3437184463988364fbd10

Source dataset

uspto-grants-2001_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06320017B1